30-Foot ‘Terror Crocodile’ Ambushed Dinosaurs at Water’s Edge

Study says the five-ton extinct reptiles had teeth the size of bananas

Deinosuchus
An illustration of the 30-foot-long, dinosaur eating crocodilian Deinosuchus. Tyler Stone

Even the mighty dinosaurs may have lived in fear of the giant extinct crocodilian Deinosuchus, whose name translates to “terror crocodile.” These monstrous swamp-dwellers reached lengths of more than 30 feet, weighed as much as 8,000 pounds and delivered bone crushing bites with teeth the size of bananas, reports Johnny Diaz for the New York Times.

Now, research published this week in the Journal of Vertebrate Paleontology revisits fossil specimens of the fearsome creature and reveals new details about their reign over the swamps of Late Cretaceous North America.

Despite their name, terror crocodiles are actually more closely related to modern alligators. But that doesn’t mean they simply looked like goliath gators, or crocodiles for that matter. Deinosuchus’ snout was long and broad with a strangely bulbous nose that featured two additional holes positioned in front of its nostrils, according to the paper. The researchers aren’t sure why Deinosuchus had such a honking nose or what those extra holes were for.

"Most people think crocodiles haven't changed in 75 million years," Adam Cossette, a paleobiologist at the New York Institute of Technology College of Osteopathic Medicine of Arkansas State University and the paper’s lead author, tells Gabriela Saldivia of NPR. "This study shows that the ancestors of today's American alligator didn't look anything like them."

After studying the tooth-studded maws of these unfamiliar-looking reptilian giants, Cossette tells the Times he’s confident they would have posed a credible threat to the huge dinosaurs that walked the Earth at the time. This finding broadens the prior understanding of the animal’s feeding habits, which had been assumed to be more opportunistic than selective.

Poring over Deinosuchus remains also revealed that there were not one but three species that lived across North America between 75 million and 82 million years ago, reports Allen Kim for CNN. Two species, Deinosuchus hatcheri and Deinosuchus riograndensis, occupied the west from modern-day Montana to northern Mexico. The third lay in wait in the Atlantic coastal plain from New Jersey to Mississippi.

"Some of them were separated by a seaway that at one point cut North America in half from what's now the Gulf of Mexico up to the Arctic Ocean," Christopher Brochu, a paleontologist at the University of Iowa and the study's co-author, tells NPR. "And that may have driven what we call speciation. There might have been one ancestral Deinosuchus form in North America, and then the seaway cut that population in half and on one side it evolved in one direction, the other side in a different direction."

Mark A. Norell, the curator and chair of paleontology at the American Museum of Natural History, tells the Times the new findings highlight how much there is left to learn about these creatures, which are rare and understudied.

“Usually their collection and study is an afterthought,” he tells the Times, “as most work done on these formations and deposits is dominated by dinosaurs.”